Current flow interrupter utilizing a tiltable chamber



April 1969 B. H. NICOLAISEN 3,440,327

CURRENT FLOW INTERRUPTER UTILIZING A TILTABLE CHAMBER Filed Jan. 30, 1967 United States Patent 3,440,327 CURRENT FLOW INTERRUPTER UTILIZING A TILTABLE CHAMBER Bernard H. Nicolaisen, Stamford, Conn., assignor to Olin Mathieson Chemical Corporation Filed Jan. 30, 1967, Ser. No. 612,647 Int. Cl. H01b 7/34, 9/06 US. Cl. 174-15 12 Claims ABSTRACT OF THE DISCLOSURE Apparatus for interrupting the flow of electrical current through flowing liquid electrical conductors wherein a chambered cup tilts alternately in opposite directions to interrupt periodically the fiow of liquid conductor and to form electrically separated portions and then recombining the portions.

This invention relates to improved current interrupters for use in interrupting current flow in flowing liquid electrical conductors. More particularly, this invention relates to improved current interrupters especially for use with electrolytic cells having flowing mercury cathodes. Still more particularly, this invention relates to current interrupters of the tilting chamber type, improved in simplicity, rugged and reliable, self-operating and requiring substantially no maintenance.

Current interrupters are used in electrical operations using conductive liquids to prevent leakage of electric current through the liquid in undesired directions. For example, in operating a plurality of mercury cells, connected to a central decomposer or in arrangements of oxidizing cellsor fuel cells wired to recover electric current and return current and mercury to the electrolytic cell, current interrupters are used to prevent flow of electric currents in undesired directions through the flowing stream of mercury or amalgam.

Several designs for current interrupters are known to the art. Some depend upon free fall of filamentous streams of mercury which break up into droplets due to gravitational acceleration. These types are disadvantageous in that the free fall requires tall and cumbersome equipment. Moreover, the holes through which the mercury or amalgam flow are subject to plugging.

Another type of current interrupter consists of rotating concentric cylinders as described in French Patent 1,370,- 834. This design has the disadvantages that a shaft seal is needed around the shaft which drives the cylinders and the speed of rotation must be adjusted to match amalgam flow.

Non-conducting Archimedes screws have also been proposed as current interrupters but they also suffer from the problem of matching speed to mercury flow rate.

US. Patents 588,276; 631,468 and 2,876,192 show chambered tilting troughs for mercury distribution or current interruption or both, but all appear to have the defect that, at the moment of tilting, electrical conduction is possible between the incoming amalgam stream, the stream of amalgam pouring from the interrupter and the departing stream of amalgam.

In contrast to the current interrupters of the prior art,

the device of this invention consists of:

(A) A container having sides and a bottom and at least one outlet for liquid in said bottom;

(B) A non-conductive cup having sides and a recessed bottom and being disposed in said container; the bottom of said cup terminating at its edges in a trough; the sides of said cup extending below and spaced from said recessed bottom to form passages for liquid;

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(C) A non-conducting vertical partition standing perpendicularly to the bottom of said cup and dividing said cup into first and second substantially symmetrical chambers; said partition bifurcated at its top to form a third chamber symmetrical about the center-line of said cup and extending partially over said first two chambers;

(D) A horizontally disposed pivot supporting said cup in said container;

(E) Magnetic means disposed in said container and said cup to hold said cup at an angle to the horizontal, the force of said magnetic means being less than the gravitational force bearing on the liquid accumulated in the uppermost of said first and second chambers at overflow.

The container of the device of this invention is suitably open at the top and has a bottom outlet for liquid. It is suitably fabricated of one or a plurality of pieces. Alternatively, a cover is suitably a part of the container. It is attached, for example, by flanges, to prevent contamination of the flowing liquid and the cover suitably carries an inlet for flowing liquid. When an electrically conductive cover is provided, it is electrically insulated from the bottom of the container to prevent electrical flow from the incoming to the outgoing stream of liquid conductor. When the cover is non-conductive, it is selfinsulating and no additional insulation is necessary. The liquid inlet advantageously passes through the cover along the center-line thereof to deliver the inflowing liquid along the center-line of the cup when the cup is in horizontal position. Ordinarily the outlet is larger than the inlet to prevent accumulation of liquid in the interrupter.

The non-conducting cup, viewed from the top is of any suitable shape. In its simplest form it is circular but it can be oval or polygonal. The non-conducting cup is wholly formed of any non-conducting material or alternatively is adequately covered with non-conducting materials, hereinafter more specifically exemplified. When the cup is formed of rubber-covered steel, for example, it is sufliciently rigid to support the load it carries of liquid conductor, for example, mercury or liquid alkali metal amalgam. Materials of lesser rigidity are suitably supported by underlying cup support means of more rigid material, for example, a plate of steel, ceramic or other material. The cup support means is either conductive or not, since the flowing conductor does not contact the underlying cup support means.

The bottom of the cup is recessed between the sides of the cup and terminates at its edges in a trough adapted to retain a minor portion of liquid conductor as it flows from the third chamber, located symmetrically about the center-line of the cup, through the first or second chamber of the cup. The purpose of the trough around the bottom of the cup is to retain a minor portion of liquid conductor and thus to insure completion of the swing of the cup and engagement of the forces between the magnets and the magnetically susceptible portions of the cup.

The sides of the cup are adapted, for example, by means of a lower lip, to retain a minor portion of liquid conductor when that side of the cup is below the horizontal but to discharge liquid conductor when that side of the cup is above the horizontal. The purpose of shaping the sides and lower lip to retain a minor portion of liquid conductor is to insure completion of the swing of the cup and engagement of the forces between the magnets and the magnetically susceptible portions of the cup. The lip also serves to break the flow of liquid as a continuous, conducting stream at the time of tilting from the third chamber through the first or second chamber and directly into the body of the container. The sides of the cup extend partially below and are spaced from the bottom of the cup to form passages for discharge of liquid conductor.

from the cup to the body of the container, at the time of levelling and when no liquid flows from the third chamber.

The vertical partition dividing the cup into first and second substantially symmetrical chambers is fabricated integrally with and of the same material as the cup or, alternatively, is separately fabricated of any suitable nonconducting material and suitably attached to the bottom of the cup. This partition is bifurcated at its top to form a third chamber symmetrical about the center-line of the cup and adapted to receive the flow of liquid conductor when the cup is approximately in horizontal position. The third chamber collects incoming liquid conductor while the first or second chamber is emptying and while the liquid electrolyte is possibly contacting electrically the body of the container and outflowing liquid conductor. As tilting continues past the horizontal position, liquid electrolyte is transferred from the third chamber to the first or second chamber, whichever is uppermost at the time. In conjunction with the lower lip, this effectively prevents at all times any electrical contact between incoming and outgoing liquid conductor.

The third chamber is adapted to contain only a minor portion of the liquid conductor. It serves to break any electrical contact between incoming liquid conductor and any liquid conductor elsewhere in the container. The angle between the sides of the third chamber are constructed to discharge contained liquid conductor completely when the cup is completely tilted and while the cup is magnetically held in a tilted position.

The pivot and cup support means when used to reinforce the bottom of the cup are suitably fabricated of electrically conductive or non-conductive material so long as they are sufficiently rigid to support the load with which they are charged and wear adequately. They never contact either incoming or outgoing liquid conductor and are suitably in electrical contact with either the body of the container or with the cover since the cover, when used, is always electrically insulated from the container.

Magnetic means, as the term is used in the present specification and claims, includes magnets per se, either electromagnets and necessary electrical accessories or permanent magnets and also includes associated magnetically susceptible elements which the magnets per se act upon. Thus, magnetic means, in one instance, comprises permanent magnets mounted on the walls of the container with matching steel or other magnetically susceptible panels in the sides of the cup. Alternatively, permanent magnets also suitably form panels in the sides of the cup. Each pair of magnets, when two are in juxtaposition, are arranged to attract rather than repel each other. When the interrupter also comprises a cover, the magnetic means are suitably disposed either in the cover or elsewhere in the container. Advantageously, magnets are disposed below the line-of-travel of the cup so as to act as stop motion of the cup. Alternatively, the magnetic means are disposed with sufiicient clearance to provide sliding approach to juxtaposition. Permanent magnets are preferred for their simplicity but electromagnets with necessary associated electrical connections are preferably substituted for permanent magnets when it is desirable to provide adjustability in the magnetic force applied. In this case, too, the magnetic means suitably consist of two attracting electromagnets or an electromagnet associated with a magnetically susceptible element. Either is aflixed to a moving or stationary element of the interrupter but it is usually more convenient for the electromagnet to be afiixed to a stationary element.

The accompanying figures further exemplify the invention. FIGURE 1 shows one embodiment of the device of the invention in which permanent magnets and the tilting mechanism are affixed to the sides of the cover. FIGURE 2 shows another embodiment in which permanent magnets are affixed to the bottom of the container and the tilting mechanism is attached to the sides of the container. FIGURE 3 shows an embodiment of the invention in which an electromagnet is mounted on the sides of the container so as to stop motion of the tilting mechanism.

In FIGURE 1, container 12 has bottom 12A and sides 12B. Container 12 and cover 11 are flanged and bolted together with insulated bolts 14 and separated by insulating gasket 13. Inlet 15 for liquid extends well through cover 11 along its center-line. Outlet 16 is provided in container 12 for removal of liquid metal. Horizontal pivot 17 is supported in the walls of cover 11 and carries steel plate 18 with the transverse center-line of plate 18 parallel to the axis of pivot 17. Adherent to steel plate 18 is plastic cup 19, open at the top and having recessed bottom 20 and sides 21. The circumference of bottom 20 defines a trough 22 overlapping lip 28 of sides 21 and spaced therefrom to form drain passages 23 which are directed toward the center of the container. Steel jacket 24 encloses the sides 21 of the plastic cup 19. Magnets 25 located on the sides of cover 11 attract and hold the cup by means of steel jacket 24 when it moves into the vicinity. Upstanding from bottom 20 of the plastic cup 19 is a divider 26 of rigid plastic dividing the cup into two symmetrical non-communicating chambers. Divider 26 is bifurcated to form conical top 27 which serves as a temporary liquid reservoir during the tilting of cup 19.

FIGURE 2 has corresponding parts bearing the same numerals as FIGURE 1. Magnets 25 are mounted in the bottom 12A of container 12 and stop motion of cup 19.

FIGURE 3 has corresponding parts bearing the same numerals as FIGURE 1. Electromagnet 25A is mounted on sides 12B of container 12 and extend to stop motion of cup 19. Current is supplied to coil 25B to energize electromagnet 25A.

In an exemplary operation, amalgam flows via inlet 15 into cup 19 which is magnetically held in the tilted posi tion shown in accompanying FIGURE 1. When the weight of the liquid metal in the filling chamber is suificient to overcome the force of the magnet, cup 19 swings to the oppositely tilted position and is held there by the opposite magnet. At the mid-section of the swing incoming liquid metal is intercepted in conical top 27 and is out of contact with liquid metal emptying from the filled chamber. When the swing is completed, the intercepted liquid metal empties from conical top 27 into the then emptying chamber but it is intercepted again and retained by lip 28, avoiding electrical contact with the container. During the swing, liquid metal empties from the filled chamber through drain passages 23 into container 12. However, trough 22 retains a sufiicient portion of liquid metal to effect completion of the swing until the cup is held in a tilted position by one of the magnets. When the swing is completed, the small portion of liquid metal retained in trough 22 is transferred to cup 19 and is retained there by lip 28 until' the cup tilts in the opposite direction.

Suitably the cup is a non'conductor of electricity, is not wettable by the liquid introduced and is chemically resistant to the contacting liquid. The cup is advantageously fabricated of molded plastic sufficiently rigid to resist serious deformation when one chamber thereof is filled with liquid metal, for example, mercury or amalgam. Other non-conducting materials are also suitable provided they have sufficient strength to resist breakage, particularly when the cup oscillates rapidly to accommodate a rapid flow of liquid metal. Suitable materials include polystyrene, Bakelite, glass, ceramic, rubher-covered steel, plastic impregnated fiberglass, polypropylene and Penton, a chlorinated polyether thermoplastic polymer manufactured by Hercules, Inc. Teflon, polyethylene and polypropylene are especially suitable for use with aqueous liquids. They are non-conductive,

not wettable by aqueous liquids and are chemically resistant to them.

Suitably the cover and the container are fabricated of the same types of plastic materials as the cup which are sutficiently rigid to resist serious deformation in use with heavy liquid metals. The materials for the container need not be transparent but may be non-transparent and they may be electrically conductive provided the cover and bottom are electrically insulated. Many common metals and plastics are suitable including, for example, steel, iron, polystyrene, Bakelite, glass and fiber glass reinforced plastics. When mercury or amalgam is not the liquid, copper, brass and aluminum are also suitable.

While the interrupter of this invention finds particular utility, as shown, with streams of mercury or alkali metal amalgams, it is also useful with other liquid conductors including liquid metals, e.g., sodium (at elevated temperatures) and aqueous or non-aqueous electrolytes, e.g., aqueous sodium chloride brine, aqueous caustic, aqueous acids or solutions of sodamide in liquid ammonia. Proper choice of materials of construction of the parts will be obvious to those skilled in the art.

It is an advantage of the device of this invention, in contrast with those of the prior art, that there is no possibility at any time of the establishment of electrical flow between the incoming and outgoing streams. In the tilting chamber devices of the prior art which have only two chambers and which do not have the magnetic holding means of the device of the present invention, the first small quantity of liquid entering an empty chamber is necessarily off-center from the fulcrum or pivot. A very small amount of material is sometimes sufiicient to cause tilting and the chambers never fill near capacity. Oscillation is far more frequent and rapid than necessary or desirable. This leads to rapid wear, chattering and shorting. On the contrary, the deviceof the present invention, because of the magnetic holding means, tilts only when one chamber is Well filled and holds in its tilted position until the otherof the two symmetrical chambers is wellfilled. The advantage is a reduced rate of oscillation, less wear and no chattering. A further advantage of the device of the present invention is that it automatically compensates for variations in the rate of flow of liquid. The device cycles more frequently with increased flows and less frequently with decreased flows. The device has no externally driven mechanism and no shaft seals are required.

EXAMPLE A chambered cup, having a circular shape and a recessed bottom, essentially as shown in attached FIG- URE 1, was fabricated of ,4 inch thick polystyrene. It was 3 inches in diameter with sides 1 inch high. A partition was provided along a diameter of the cup. The partition was bifurcated to form a trough at the top which was closed at the ends by the sides of the cup. The cup was mounted on a circular steel plate 2% inches in diameter carried on a steel pin as pivot, in turn supported in pillow bearings inserted in the walls of the cover. The

, cover was ZO-gauge sheet iron having a /1 inch inlet line centered in the top and shaped generally as shown in FIGURE 1. The cover was bolted by means of insulated bolts through flanges on the cover to flanges on the bottom but separated electrically therefrom by a rubber gasket ,1 inch thick. The bottom of the container had a center outlet line A inch in diameter.

Amalgam from a mercury cathode electrolytic cell was introduced into the inlet line in the cover and removed from the outlet line in the bottom to an amalgam decomposer. However, no electric current flowed through a conductor attached to the inlet and outlet amalgam lines.

What is claimed is:

1. A current interrupter comprising:

(A) a container having sides and a bottom and at least one outlet for liquid in said bottom;

(B) a non-conductive cup having sides and a recessed bottom and being disposed in said container; the bottom of said cup terminating at its edges in a trough; the sides of said cup extending below and spaced from said recessed bottom to form passages for liquid;

(C) a non-conducting vertical partition standing perpendicularly to the bottom of said cup and dividing said cup into first and second substantially symmetrical chambers; said partition bifurcated at its top to form a third chamber symmetrical about the center-line of said cup and extending partially over said first two chambers;

(D) a horizontally disposed pivot supporting said cup in said container;

(E) magnetic means disposed in said container and said cup to hold said cup at an angle to the horizontal, the force of said magnetic means being less than the gravitational force bearing on the liquid accumulated in the uppermost of said first and second chambers at overflow.

2. A current interrupter as claimed in claim 1 in which said third chamber has the form of a cone.

3. A current interrupter as claimed in claim 1 in which said third chamber has the form of an elongated trough with closed ends.

4. A current interrupter as claimed in claim 1 in which said magnetic means are electromagnets.

5. A current interrupter as claimed in claim 1 in which said magnetic means are permanent magnets.

.6. A current interrupter as claimed in claim 1 in which said magnetic means are disposed below the line-of-travel of said cup to act to stop motion of said cup.

7. A current interrupter as claimed in claim 1 in which said magnetic means are disposed in the sides of said container.

8. A current interrupter as claimed in claim 1 in which said magnetic means are disposed in the bottom of said container.

9. A current interrupter as claimed in claim 1 in which said magnetic means continuously enclose the sides of said cup.

10. A current interrupter as claimed in claim 1 having cup support means interposed between said cup and said pivot to counteract deformation of said cup.

11. A current interrupter as claimed in claim 1 in which said container has a cover electrically insulated-from the rest of said container, said cover having an inlet for liquid extending through said cover along the center-line thereof.

12. A current interrupter as claimed in claim 11 in which said magnetic means and said cup are disposed in said cover.

References Cited UNITED STATES PATENTS 2,849,524 8/1958 Matsuo 17415 BERNARD A. GILHEANY, Primary Examiner. HAROLD BROOME, Assistant Examiner.

US. Cl. X.R 2 -2 as 4 

